Major advances have been made in preventing the occurrence of some infectious diseases (through vaccines and public health measures) and in the treatment of some infectious diseases (through the development of antimicrobial agents). However, infectious diseases remain a major global health threat, and it is clear that there is a significant national need to improve our ability to prevent, detect, and control microbial diseases. To accomplish this goal, it is essential that high quality basic science research be performed in infectious diseases and that our nation trains outstanding people to perform such research. Basic science research is necessary to elucidate the mechanisms by which microbial pathogens cause disease, to elucidate the mechanisms by which the host immune system can successfully defend against microbial pathogens, and to define novel strategies to prevent and/or treat infectious pathogens. The University of Texas Southwestern Medical Center at Dallas has an outstanding group of senior investigators performing basic science research in Infectious Diseases, and is therefore, ideally positioned to train both Ph.D. scientists interested in Infectious Diseases and physicians who are interested in laboratory-oriented research careers in Infectious Diseases. The major goal of our proposal is to provide outstanding laboratory research training in Infectious Diseases to Ph.D. and M.D. postdoctoral fellows so that these individuals may develop into successful independent investigators who will become future leaders in the field. This will be accomplished by providing focused training with outstanding preceptors who conduct state-of-the-art research in different aspects of host-pathogen interactions, by providing 1) a highly stimulating multidisciplinary environment for research, 2) close supervision and support from training grant faculty, and 3) didactic training in both practical aspects of research and career development (e.g., ethics, biostatistics, manuscript and grant writing, patent and proprietary issues) as well as didactic training in diverse areas of science (e.g., current topics at the interface of host-pathogen interactions, immunology, cell biology, molecular biology, virology) that will enrich their research training experience and enhance the quality of their research. Together with the outstanding scientific environment at UT Southwestern, this multi-faceted approach to training post-doctoral fellows in Infectious Diseases research will produce an outstanding group of young investigators with strong potential to make valuable contributions to the global prevention and/or treatment of infectious diseases.